Improvement in keys or packing-blocks for bridges



UNITED STATES PATENT OFFICE,

NEWTON CHAPIN, OF CHICAGO, ILLINOIS.

IMPROVEMENT IN K'EYSOR PACKING-BLOCKS FOR BRIDGES.

Specification forming part of Letters PatentNo. 44,398, dated September 27, 1864; antedated June 28, 1884.

.To a/ZZ whom it may concern:

Beit known that I, NEWTON CHAPIN, of Chicago, in the county ot' Cook and State of Illinois, have invented a new and useful Improvement in Iron Keys for Bridges; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings and the letters and figures marked thereon, which form part of this specification.

In said drawings, Figure l represents a per spective view ofthe chord of a bridge, showing the application of my invention. Fig. 2 :is` a side view of my invention, and Fig. 3 is a vertical section of the same, showing the interior construction thereof'. y

The nature of my invention consists in making an iron key to be used in the construction of bridges, in the form of a rectangular block, or substantially in that form, and having the stme cast hollow, and provided with one or more partitions arranged in such a manner in respect to the direction of the strain that the said hollow block has all the strength necessary for the accomplishment of the purpose for which it is used, and at the same time is much lighter and cheaper than the solid block keys heretofore used.

To enable those skilled in the art fully to understand how to make and use my invention,rI will proceed to describe the same with particularity, reference being made to the aforesaid drawings.

A B B represent the timbers composing the chord of the bridge, and C represents my invention, which may be provided with the ears c c, to preventtheir sliding through between the timbers;`or they may be made slightlynarrower at the bottom than at the top, so that when placed in the grooves in the timbers of corresponding shape the said keys will be prevented from dropping through without the ears c c.

b b represent the horizontal partitions before mentioned, which are employedl for the purpose of strengthening the keys, for, these keys being used to keep the different timbers from sliding longitudinally by and independent ofeach other, whena strain is applied to or comes upon th`e same, it is evident that the str-aiu comes at the corners of the key situated diagonally with respect to each other, and in tlle direction of the plane of the said partitions b b, which, therefore, render the keys of sufficient strength to resist the pressure upon the same.

a represents holes through the sides of the keys, at which the core is taken out from the casting, and through which bolts or rods may pass, to hold the timbers irmly together. The timbers composing the chord are placed at a small distance apart, and a notch or groo\ e cut in the adjacent sides ot' the timbers, into which the keys are placed, as shown in the drawings.

I) D represent two clamps, which arelet into the timbers B B' and connected by a rod, to

hold the said timbers together, and isused wherever it is necessary to splice the timbers composing the chord. rate application for this invention, no further description of the same is given.

What I claim as my invention, and desire t0 secure by Letters Patent, is

Constructing an iron key for bridges in the form ot a hollow shell, and providing the same with one or more partitions, b b, substantially as and for the purposes described.

NEWTON CHAPIN. Witnesses z F. E. WALKER, W. E. MARES.

Having made a sepa- 

